From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86EB7C46471 for ; Tue, 7 Aug 2018 18:52:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 454D52170A for ; Tue, 7 Aug 2018 18:52:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 454D52170A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403889AbeHGVIg (ORCPT ); Tue, 7 Aug 2018 17:08:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33092 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726419AbeHGVIf (ORCPT ); Tue, 7 Aug 2018 17:08:35 -0400 Received: from localhost (unknown [194.244.16.108]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 4E80CD01; Tue, 7 Aug 2018 18:52:52 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bart Massey , Dave Kleikamp , jfs-discussion@lists.sourceforge.net, Kees Cook Subject: [PATCH 4.17 06/18] jfs: Fix usercopy whitelist for inline inode data Date: Tue, 7 Aug 2018 20:51:09 +0200 Message-Id: <20180807172313.194184605@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180807172312.964272530@linuxfoundation.org> References: <20180807172312.964272530@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kees Cook commit 961b33c244e5ba1543ae26270a1ba29f29c2db83 upstream. Bart Massey reported what turned out to be a usercopy whitelist false positive in JFS when symlink contents exceeded 128 bytes. The inline inode data (i_inline) is actually designed to overflow into the "extended area" following it (i_inline_ea) when needed. So the whitelist needed to be expanded to include both i_inline and i_inline_ea (the whole size of which is calculated internally using IDATASIZE, 256, instead of sizeof(i_inline), 128). $ cd /mnt/jfs $ touch $(perl -e 'print "B" x 250') $ ln -s B* b $ ls -l >/dev/null [ 249.436410] Bad or missing usercopy whitelist? Kernel memory exposure attempt detected from SLUB object 'jfs_ip' (offset 616, size 250)! Reported-by: Bart Massey Fixes: 8d2704d382a9 ("jfs: Define usercopy region in jfs_ip slab cache") Cc: Dave Kleikamp Cc: jfs-discussion@lists.sourceforge.net Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- fs/jfs/jfs_dinode.h | 7 +++++++ fs/jfs/jfs_incore.h | 1 + fs/jfs/super.c | 3 +-- 3 files changed, 9 insertions(+), 2 deletions(-) --- a/fs/jfs/jfs_dinode.h +++ b/fs/jfs/jfs_dinode.h @@ -115,6 +115,13 @@ struct dinode { dxd_t _dxd; /* 16: */ union { __le32 _rdev; /* 4: */ + /* + * The fast symlink area + * is expected to overflow + * into _inlineea when + * needed (which will clear + * INLINEEA). + */ u8 _fastsymlink[128]; } _u; u8 _inlineea[128]; --- a/fs/jfs/jfs_incore.h +++ b/fs/jfs/jfs_incore.h @@ -87,6 +87,7 @@ struct jfs_inode_info { struct { unchar _unused[16]; /* 16: */ dxd_t _dxd; /* 16: */ + /* _inline may overflow into _inline_ea when needed */ unchar _inline[128]; /* 128: inline symlink */ /* _inline_ea may overlay the last part of * file._xtroot if maxentry = XTROOTINITSLOT --- a/fs/jfs/super.c +++ b/fs/jfs/super.c @@ -967,8 +967,7 @@ static int __init init_jfs_fs(void) jfs_inode_cachep = kmem_cache_create_usercopy("jfs_ip", sizeof(struct jfs_inode_info), 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT, - offsetof(struct jfs_inode_info, i_inline), - sizeof_field(struct jfs_inode_info, i_inline), + offsetof(struct jfs_inode_info, i_inline), IDATASIZE, init_once); if (jfs_inode_cachep == NULL) return -ENOMEM;